What is Medical Thermography?
Medical thermography, also known as infrared thermography, thermal imaging, infrared radiometry, or infrared imaging, is a non-invasive diagnostic technique that allows the examiner to visualise and quantify changes in skin surface temperature using ultra-sensitive infrared cameras.
Infrared Radiation is that portion of the electromagnetic spectrum that extends from the long wavelength, or the red end of the visible-light range to the microwave range. Invisible to the eye, it can be detected as a sensation of warmth on the skin. In principle, infrared radiation is emitted by every object above absolute zero, (-273°C) - natural or thermal radiation
Thermographic images are referred to as Thermograms.
Infrared (IR) thermography is based on analysis of skin surface temperatures as a reflection of normal or abnormal human physiology using a highly specialized IR-camera. In a fraction of a second, a large area of the human body can be imaged to an accuracy of less than 0.1°C as well as a spatial resolution of 25-50 micrometers (6) and, dynamic responses to stimuli are easily documented.
A poster produced by the United Kingdom Thermography Association (UKTA) entitled "Applications of Infrared Thermography in Medicine" also nicely demonstrates the scope of this technology.
Today, infra red thermal imaging has become one of the most efficient techniques for the study of skin temperature. Modern, infra-red digital cameras, employing focal-plane array technology, provide a sensitive diagnostic tool for a multitude of clinical and experimental situations, ranging from breast cancer screening to open heart surgery. Thirty years of clinical use and more than 8,000 peer-reviewed studies in the medical literature have established thermography as a safe and effective means to examine the human body (Ammer & Ring, 1995; Cockburn , 2000). It is completely non-invasive, and as such does not require the use of radiation or other potentially harmful elements. Medical research has shown thermography to be a useful tool in research as well as being helpful in the diagnosis of Breast Cancer, Nervous System Disorders, Metabolic Disorders, Neck and Back Problems, Pain Syndromes, Arthritis, Vascular Disorders, and Soft Tissue Injuries among others (see Ammer & Ring, 1995 for references).
Many base line thermographic studies have been performed which show the anticipated normal pattern of temperature in a thermal image, both in steady state as well as dynamic situations, as for example during skin heating and cooling. Characteristic changes in the normal pattern are associated with different pathological phenomena. These changes provide the basis to be able to carry out objective non-invasive investigations, which are of diagnostic value.
It is not the intention of this web site to go into detail concerning the technological developments behind modern day infrared thermal imaging devices, nor to go into detail regarding the physiological mechanisms which effect skin surface temperature. For an up to date review on Medical Thermography, the reader is referred to the recent (2006) edition of the The Biomedical Engineering Handbook. Medical Devices and Systems. FL, USA: CRC Press 2006. ISBN 0-8493-2122-0. In section III of this book there are 21 chapters dedicated to Medical Infrared Imaging written by International experts which cover aspects varying from camera design to advances in thermal imaging processing.
Further information can also be found in the links section of this web site
Ammer & Ring (1995) The Thermal Image in Medicine and Biology. Ammer, K. & Ring, E.F.J. (eds). Uhlen-Verlag, Wien, 1995.
Cockburn, W. (2000).What is clinical Thermography http://www.iact-org.org/patients/what-is-thermography.html